Photochromic compositions in a lauryl methacrylate polymeric binder

ABSTRACT

PHOTOCHROMIC COMPOSITIONS COMPRISING A POLYMER OF LAURYL METHACRYLATE HAVING DISPERSED THROUGHOUT THE BODY THEREOF VARIOUS BENZOSPIROPYRAN COMPOUNDS ARE DESCRIBED.

3,565,814 SITIONS IN A LAURYL METHACRYL ATE Feb. 23, 1971 v.1. J. PELLONPHOTOCHROMIC COMPO POLYMERIC BINDER Filed 06%. 27, 1967 IRRAD/A T/O/VTIME L 06 SEED/V0.5

INVENTOR. JOSEPH JAG/N70 PELLO/V ATTORNEY United States Patent O3,565,814 PHOTOCHROMIC COMPOSITIONS IN A LAURYL METHACRYLATE POLYMERICBINDER Joseph Jacinto Pellon, New Canaan, Conn., assignor to AmericanCyanamid Company, Stamford, Conn., a corporation of Maine Filed Oct. 27,1967, Ser. No. 678,591 Int. Cl. G03c N72 US. Cl. 252-300 3 ClaimsABSTRACT OF THE DISCLOSURE Photochromic compositions comprising apolymer of lauryl methacrylate having dispersed throughout the bodythereof various benzospiropyran compounds are described.

BACKGROUND OF THE INVENTION The instant invention resides in the fieldof photochromic compositions. It is more particularly directed tophotochromic compositions comprising polymers of lauryl methacrylatewhich have dispersed throughout the body thereof variousbenzospiropyrans.

The incorporation of benzospiropyrans into polymeric matrices has beenknown in the prior artv For example, US. Pat. No. 3,212,898 disclosesthe use of such benzospiropyrans in polyester resins.

While the prior art systems have been found adequate for many serviceapplications, they tend to suffer from the inability to change colorvery rapidly when subjected to ultraviolet or other light.

SUMMARY I have now found that the sensitivity of benzospiropyranphotochromic compositions, i.e., their rate of color change per unit ofexposure, can be materially and drastically increased by incorporatingthem into a polymer of lauryl methacrylate rather than other polymersystems. The re sultant compositions are more easily and rapidlyactivated in service and therefore enable applications to which they aresubjected to be more economically conducted. They are useful in allareas wherein known systems are used, such as data display, signalprocessing, information storage, photographic dodging, automobileWindshields, eyeglass lenses, containers, memory devices, such asoptical analogue computers, temporary oscillographs, light switches,optical masks, jewelry, toys, advertising articles and the like.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing is a graphicrepresentation showing the change in optical density at 555 III/.4 of acomposition comprising poly(lauryl methacrylate) and 3% of 1',3,3'trimethyl 6 nitro8'-meth0xy-spiro(2H-1- benzopyran-2,2'-indolene),represented by the open circle and a second composition comprisingpoly(methyl methacrylate) and 7% of the same spiropyran compoundrepresented by a closed circle (9). Both compositions are in the form ofunsupported films, the lauryl film being 1.0 mil thick and the methylfilm being 0.7 mil thick. As can be readily seen the poly(laurylmethacrylate) film reaches a higher change in optical density than thepoly (methyl methacrylate) film in a shorter irradiation time. Bothcurves were plotted by recording the optical density change of the twocompositions produced in Example 1, below.

3,565,814 Patented Feb. 23, 1971 DESCRIPTION OF THE INVENTION INCLUDINGPREFERRED EMBODIMENTS The benzospiropyran compounds which are useful asthe photochromic additives of the present invention are well known inthe prior art and have the general formula:

wherein R, R and R represent the same or different alkyl radicals having1 to 20 carbon atoms, inclusive, and R and R taken together form asaturated carbocyclic ring, R is hydrogen or an alkyl radical having 1to 20 carbon atoms, inclusive, X, X X X Y, Y Y and Y represent hydrogen,an alkoxy radical having 1 to 4 carbon atoms, inclusive, a nitro radicalor a halogen radical, and the individual pairs Y and Y Y and Y Y and Y Xand X X and X or X and X when taken together, form a conjugated aromaticring.

These compounds are well known in the art as are methods for theirpreparation. For example, US. Pats. Nos. 2,953,454 and 3,022,318 teachvarious compounds and methods for their preparation, while copendingapplication, Ser. No. 239,334, filed Nov. 21, 1962, now abandoned byCerreta et al., teaches others, said references hereby beingincorporated herein by citation.

Examples of the compounds which correspond to Formula I include l,3 ,3-trimethyl-5 ',6-dinitro-spiro (2H- 1 -benzopyran- 2,2'-indoline)1,3,3-trimethyl-5',6-dinitro-8-rnethoxy-spiro(2H-1-benzopyran-2,2'-indoline)1',3,3-trimethyl-5',8-dinitro-6-methoxy-spiro(ZH-lbenzopyran-2,2'-indoline),1',3',3-tributyl-8-chlor0-6' butoxy-spiro(2H-l-benzopyran-2,2-indoline)1-octyl-3-methyl-3-ethyl-3-propyl-4',7-diethoxyspiro(2H-1-benzopyran-2,2'-indoline),1,3',3-tristearyl-3-butyl-S,6-benzo-6-fluoro-spiro(2H-lbenzopyran-2,2'-indoline),l,3',3'-trimethyl-6-nitro-6,7'-benzo-spiro(2H-l-benzopyran-2,2'-indoline),1',3',3'-triethyl-7-bromo-4',7'-dimethoxy-spiro(2H-lbenzopyran-2,2-indoline),1,3,3'-trimethyl-6-nitro-spiro(2H-1-benzopyran-2,2'-

indoline) l, 3 ',3 '-trimethyl-8-nitro-spiro (2H-1-benzopyran-2,2-

indoline) 1,3 ,3 -trimethyl-6-nitro-8-methoxy-spiro( 2H-l-benzopyran-2,2-indoline), l,3 ,3 -trimethyl-5-nitro-8-methoxy-spiro(2H- l-benzopyran-2,2-indo1ine 1', 3 ',3-trimethyl-6-chloro-8-nitro-spiro(2H-1-benzopyran-2,2-indoline1-methyl-3'-cyclohexyl-5,8-dichloro-5-methoxy-7'- iodo spiro(2H1-benzopyran-2,2'-indoline) and the like.

The amount of photochromic material incorporated into the laurylmethacrylate polymer is not critical and depends generally upon theintensity of the color of the composition desired upon irradiationthereof, i.e., the more compound added, the greater the color intensity.However, an amount of photochromic material ranging from about 0.01% toabout 20%, by weight, preferably about 0.05% to about 5.0%, by weight,based on the weight of the lauryl methacrylate being polymerized orlauryl methacrylate polymer, may be used.

The lauryl methacrylate may be used alone as a homopolymer or inconjunction with up to 50%, by weight, of a comonomer, such as thosehaving the formula:

a (III) I C=CH wherein R is hydrogen or a lower alkyl radical having 1to 4 carbon atoms, inclusive, and R is hydrogen, a lower alkyl radicalhaving 1 to 4 carbon atoms, inclusive, or a halogen radical. Suitablemonomers represented by this formula include styrene, methyl styrene,ethyl styrene, propyl styrene, butyl styrene, chloro styrene, bromostyrene, fiuoro styrene, iodo styrene, a-methyl styrene, a-ethylstyrene, a-butyl styrene, a-methyl methylstyrene, a-methyl ethylstyrene,lot-butyl ethylstyrene, u-ethyl chlorostyrene, vxpropyl iodostyrene andthe like.

Examples of other applicable comomeric compounds which may becopolymerized with the lauryl methacrylate include the unsaturatedalcohol esters, more particularly the allyl, methallyl, crotyl,l-chloroallyl, 2-chloroallyl, cinnamyl, vinyl, methvinyl, l-phenylallyl,butenyl, etc., esters of saturated and unsaturated aliphatic andaromatic monobasic and polybasic acids such, for instance, as acetic,propionic, butyric, valeric, caproic, crotonic, oxalic, malonic,succinic, glutaric, adipic, pimelic suberic, azelaic, sebasic,citraconic, mesaconic, itaconic, acetylene, dicarboxylic, aconitic,benzoic, phenylacetic, phthalic, terephthalic, benzoylphthalic, etc.,acids; the saturated monohydric alcohol esters, e.g., the methyl, ethyl,propyl, isopropyl, butyl, sec-butyl, amyl, etc.; esters of ethylenicallyunsaturated aliphatic monobasic and polybasic acids, illustrativeexamples of which appear above,'vinyl cyclic compounds (includingmonovinyl aromatic hydrcarbons), e.g., styrene, o-, m-, andp-chlorostyrenes, -bromostyrenes, -fluorostyrenes, -methylstyrenes,-ethylstyrenes, -cyanostyrenes, the various poly-substituted styrenessuch for example, as the various di-, tri-, and tetra-chlorostyrenes,-bromostyrenes, -fluorostyrenes, -methylstyrenes, -ethylstyrenes,-cyanostyrenes, etc., vinyl naphthalene, vinylcyclohexane, vinyl furane,vinyl pyridine, vinyl dibenzofuran divinyl benzene, trivinyl benzene,allyl benzene, diallyl benzene, N-vinyl carbazole, the various allylcyanostyrenes, the various alpha-substituted styrenes andalphasubstituted ring-substituted styrenes, e.g., alpha-methyl styrene,alpha-methyl-paramethyl styrene, etc.; unsaturated ethers, e.g., ethylvinyl ether, diallyl ether, ethyl methallyl ether, etc.; unsaturatedamides, for instance, N-allyl caprolactarn, acrylamide, andN-substituted acrylamides, e.g., N-methylol acrylamide, N-allylacrylamide, N-methyl acrylamide, N-phenyl acrylamide, etc.; unsaturatedketones, e.g., methyl vinyl ketone, methyl allyl ketone, etc.; methylenemalonic esters, e.g., methylene methyl malonate, etc.; ethylene;unsaturated polyhydric alcohol (e.g., butenediol, etc.) esters ofsaturated and unsaturated a'liphatic and aromatic, monobasic andpolybasic acids.

Other exmples of monomers that can be copolymerized with laurylmethacrylate include the vinyl halides, more particularly vinylfluoride, vinyl chloride, vinyl bromide and vinyl iodide, and thevarious vinylidene compounds, including the vinylidene halides, e.g.,vinylidene chloride, vinylidene bromide, vinylidene fluoride andvinylidene iodide, other comonomers being added if needed in order toimprove the compatibility and copolymerization characteristics of themixed monomers.

Among the monomers which are preferred for use in carrying my inventioninto effect are, for example, compounds such as acrylonitrile, and othercompounds, e.g., the various substituted acrylonitriles (e.g.,methylacrylonitri-le, ethacrylonitrile, phenylacrylonitrile, etc.), thevarious N-substituted acrylamides and alkacryla-mides, for instance,N-dialkyl acrylamides and methacrylamides, e.g., N-dimethyl, -diethyl,-dipropyl, -dibutyl, etc., acrylamides and methacrylamides and the like.

The photochromic spiropyrans may be incorporated into the laurylmethacrylate polymer after the polymer is formed, by, for example,dissolving both components in a common solvent, or by adding thespiropyran during the polymer production.

The actual polymerization process employed during which the photochromicmaterial may be completely and uniformly dispersed throughout the laurylmethacrylate polymer during polymerization is not critical, andgenerally any known process for the polymerization of the monomer may beemployed. The exact process used in each instance is governed by thephotochromic material which is to be incorporated into the resultingpolymer. For example, a polymerization process should be selected whichdoes not require the use of any material, substance, compound orcondition which will neutralize or react with the photochromic material,thereby nullifying the reversible color change ability of thephotochromic compound. In other words, if any material in a predominantexcess, such as an acid catalyst or other functional compound, or achain length regulator such as a mercaptan, is a necessary ingredient ofthe polymerization process, that process cannot be used to produce thecompositions of the present invention, since spiropyrans are sensitiveto these ingredients. The use of polymerization systems of this kindcause a decrease in the ability of the spiropyran to reverse its color.

The same is true of processes necessitating conditions of hightemperature etc. wherein the organic spiropyran is destroyed. Apolymerization method which may be used for example, comprisesconducting the polymerization in the presence of a free-radicalgenerating catalyst (and a polymerization regulator) at temperatures offrom about 10 C. to C. Any known free-radical generating catalyst whichinitiates the polymerization of the lauryl methacrylate may be used.Suitable catalysts include, for example, the organic peroxides such asmethyl ethyl ketone peroxide, benzoyl peroxide; the hydroperoxides suchas cumene hydroperoxide; the persulfate type compounds such as potassiumpersulfate, or catalysts such as azobisisobutyronitrile and the like.Additionally, such catalysts as lauroyl peroxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexane, the dialkyl peroxides, e.g.,diethyl peroxide, dipropyl peroxide, dilauryl peroxide, dioleylperoxide, distearyl peroxide, di(tertiary-butyl)peroxide anddi(tertiary-amyl) peroxide, such peroxides often being designated asethyl, propyl, lauryl, oleyl, stearyl, tertiary-butyl and tertiary-amylperoxides; the alkyl hydrogen peroxides, e.g., tertiary-butyl hydrogenperoxide (tertiary-butyl hydroperoxide), tertiary-amyl hydrogen peroxide(tertiarysolution of the polymer. The apparatus which simultaneouslydevolatilizes and extrudes the material comprises a chamber with one ormore screws having a close tolerance with the wall for compounding thematerial in its passage therethrough, and at least one vacuum chamberamyl hydroperoxide), etc.; symmetrical diacyl peroxides, 5 for removingthe volatile components of the mixture. for instance, peroxides whichcommonly are known under The terms photochromrc compoun d, photochromicsuch names as acetyl peroxide, propionyl peroxide, lauroyl t c ofPhOtOChIOmlC material, as used In the peroxide, stearoyl peroxide,malonyl peroxide, succinyl stapt l c p n s, substances, of peroxide,phthaloyl peroxide, benzoyl peroxide, etc.; un- 10 terials which changetheir transmission or reflectance upon symmetrical or mixed diacylperoxides, e.g., acetyl benzoyl being subjected to ultrav oletor VlSlblCirradlatlon and peroxide, propionyl benzoyl peroxide, etc.; terpeneoxides, Subsequently revert to thelr Oflglhal Stat? PP sublechoh e.g.,ascaridole, etc.; and salts of inorganic per-acids, e.g., thfifeof to adiihirent wavelength of Iadlatlbh, 0T removal ammonium persulfate,sodium persulfate, sodium per- 0f ihell'lltlal ra o carbonate, potassiumpercarbonate, sodium perborate, h COIIIPOSIUOHS 0f h lhyehhon y befhrther potassium perborate, sodium perphosphate, potassium modifiedwith such materials as fillers, dyes, lubricants, perphosphate, etc.Other examples of organic peroxide plasticizers, colorants, stabilizers,etc. It is also possible catalysts which may be employed are thefollowing: t0 lengthen thfi hfe 0f the q p f y h lf tetralinhydroperoxide, tertiary-butyl diperphthalate, Various amounts of anultraviolet light stablllzer into the tertiary-butyl perbenzoate,2,4-dichlorobenzoyl peroxide, COIHPOSIUOIIS- h thls manhef thePhotochfomlc hfelof the urea peroxide, caprylyl peroxide,p-chlorobenzoyl peroxadded behlosplfopyrahs 1S lbhgthehed y P q s anide, 2,2-bis(tertiary-butylperoxy)butane, hydroxyhept l extraneousamount of ultrav olet light from commg into peroxide, the diperoxide ofbenzaldehyde and the ik contact with the photochromic material. Whenabsorbers Catalyst concentrations ranging from 0.0001 to 5.00 parts, ofthl$ p are added, amounts P to about 20%, by by weight, based on theweight of the monomer employed Welght, based'oll the W igh Of thepolymer, may be used. may advantageously be used. The following examplesare set forth for purposes of If emulsion polymerization processes areemployed any illustration only and are not to be construed aslimitations available emulsifier may be used, with compounds such on oinstant l ventlon. All parts and percentages are as fatty acid soaps,rosin soaps, sodium lauryl sulfate, by Welght unless OtheFWlsespeclfiednon-ionic emulsifiersd such las pglyethorlty alkylatedpliitilnolsi EXAMPLE 1 compounds such as iocty so ium su osuccinate iexy sodium sulfosuccinate and the like, in amounts ranging To Sultable.vessel are added parts of Poly(lau.ryl from about1% 18%, by Weightpreferably 4% to 5%, methacrylate) in toluene representing a solutionhaving by weight based on the amount monomer employed an 18% solidscontent. To this solution are added 3 parts being exernplary ofl,3',3'-trimethyl-6-nitro-8-meth0xy-spiro(ZH-l-benzo- The samelimitations of procedure must also be placed The mlxture 1s stlried ithe spiroupon the physical blending techniques when the photopyran isdissolved. The resultantsolutron is then drawn chromic material isblended with the lauryl methacrylate 2 g atplece 2 glasslald g i gtemperature polymer utilizing various devices to admix the polymer orours 0 pro a ml 16 and the photochmmic compounds 40 The resultant film15 stripped from the glass substrate When physical blending of thepolymer and photoand lrradlated W ml.wayelength of hght' The chromicsubstance is desired, known procedures such as l 9 m Optlcal density isrecorded versus h utilizing a ball mill, a tumbler mixer, hot rolls,emulsion lgadlanon g g i curve i i blending techniques, Banbury mixers,Waring Blendors s 0 e on e rawmg an represente y e and the like areeifective. Another procedure which may 49 open i i be employed is knownas a devolatilization-extrusion A 9" film (0] H111) of.poly'(methy1.niethacrylate) method wherein se arate streams ofsolutions of the contammg 7% of the Same Splropyran exhlblted a Slower dh t t 1 t dt optical density change after a longer irradiation time thanI ymel' an P 0C flf P are 511 e 0 the lauryl methacrylate film under thesame conditions of mg, compounding, devolati ization and extruslon 1ncom- 50 exposure. The plot of the curve recorded testing the methylmercially ava lable devices. In the devolatilizer-extruder, methacrylatefilm is Shown on the drawing by a closed the mlxture is worked in achamber under heat and 1 vacuum so that new surfaces of the polymermixture are Following th procedure of Example 1, various othercontlnuously and rapldlybxposed to vacuum to remove spiropyran compoundsrepresented by Formula I are inthe solvent befor e tr dl g P t. The t rcorporated into various lauryl methacrylate polymers. In VolahhZatlOn asherein p yed refers to the step In each instance, the sensitivity isgreater than in known which the nonpolymeric material is removed fromthe systems. The results are set forth in Table I, below:

TABLE I Polymer Benzopyran compound Cone. Percent Example 2 Laurylmethacrylate/methacrylic 1,3,3-trimethyl-G-nirto-spiro(2H-1- 1.0

acid (95/5) copolymer. benzopyran2,2-indollne). 3Laurylmethacrylate/ethyl acrylate1,3,3-trimethyl-fi-chl0ro-8-nitro-spiro(.ZH-l- 2.5

(95/5) copolymer. henzopyran-Q,2'-indoline). 4 Laurylmethacrylate/vinylbenzene 1,3,3-trimethyl-5,6-dinitro-S-methoxy-spiro- 0.50

(00/10) copolymer. (2 H-l-benzopyran-2,2-indoline). 5Laurylmethacrylate/styrene/1,3,3-tributyl-6-nitro-6,7'-benzo-spiro(2H-1- 0.25

acrylonitrile (/15/10) terpolyrner. benzopyran-2,2indoline). 6Poly(lauryl methacrylate) l,3,3-trimethyl-6-nitro-8-butoxy-spiro(2H-15.0

benzopyran-2,2-indoline) 7 Lauryl methacrylate/styrene (/20)1,3,3-trime'thyl-5,6-dinitro-spiro(2H-1- 10.0

copolymer. benzopyran-2,2-indoline) 8 Lauryl methacrylate/acrylonitrile1,3,3-trimethy1-5-iodo-spiro-(fl H-l-benzopyran- 4. 5

(50/50) copolymer. 2,2-indoline). 9 Polyflauryl methacrylate)1,3.3-trimethyl-7-bromo-4,7-dimethoxy- 3.0

spiro (2H-1-b enzopyran-2,2-indoline) 10 Laurylmethacrylate/vmylchloride 1,3' 3-trimethyl-5',P-dinitroG-ethoxy-spiro(2H- 1.5

(/5 )copolymer.

l-benzopyran-2,2-indoline).

wherein R, R and R individually represent an alkyl radical having from1-4 carbon atoms, inclusive, R is hydrogen or an alkyl radical of 1-4carbon atoms, inclusive, X, X X X Y, Y Y and Y represent hydrogen, analkoxy radical of 1-4 carbon atoms, inclusive, a nitro radical or ahalogen radical and the individual pairs Y 20 and Y Y and Y Y and Y Xand X X and X or X and X when taken together, form a conjugated aromaticring.

2. A composition according to claim 1 wherein said polymer ispoly(laury1 methacrylate).

3. A composition according to claim 1 wherein said compound is1,3,3-trimethyl-6-nitro-8-methoxy-spiro- (2H-l-benzopyran-2,2'-indoline) References Cited UNITED STATES PATENTS3,212,898 10/ 1965 Cerreta 9690 3,329,502 7/1967 Ullman 9690 3,450,5336/1969 Amidon et al. 96-90 NORMAN G. TORCHIN, Primary Examiner R. E.FICHTER, Assistant Examiner U.S. Cl. X.R. 969O

